pmdazswap is a Performance Metrics Domain Agent (PMDA) which
exports metric values about compressed swap operation, as tracked
by the zswap Linux kernel module.
Zswap is a lightweight compressed cache for swap pages. It takes
pages that are in the process of being swapped out and attempts
to compress them into a dynamically allocated RAM-based memory
pool. Zswap trades CPU cycles for potentially reduced swap I/O.
This tradeoff can also result in a performance improvement if
reads from the compressed cache are faster than reads from a swap
This PMDA exports metrics about pool size, number of pages
stored, and various counters for the reasons pages are rejected.
Install the zswap PMDA by using the Install script as root:
# cd $PCP_PMDAS_DIR/zswap# ./Install
To uninstall, do the following as root:
# cd $PCP_PMDAS_DIR/zswap# ./Removepmdazswap is launched by pmcd(1) and should never be executed
directly. The Install and Remove scripts notify pmcd(1) when the
agent is installed or removed.
installation script for the pmdazswap agent
undo installation script for the pmdazswap agent
default log file for error messages from pmdazswap
Environment variables with the prefix PCP_ are used to
parameterize the file and directory names used by PCP. On each
installation, the file /etc/pcp.conf contains the local values
for these variables. The $PCP_CONF variable may be used to
specify an alternative configuration file, as described in
This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at
⟨http://www.pcp.io/⟩. If you have a bug report for this manual
page, send it to firstname.lastname@example.org. This page was obtained from the
project's upstream Git repository
⟨https://github.com/performancecopilot/pcp.git⟩ on 2020-12-18.
(At that time, the date of the most recent commit that was found
in the repository was 2020-12-18.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
Performance Co-Pilot PCP PMDAZSWAP(1)